He accompanied Papen to Rome as a journalist, a representative for the Hamburger Nachrichten, for the signature of the Reichskonkordat between Nazi Germany and the Holy See, shortly after Adolf Hitler's rise to power.

After World War II Dertinger co-founded the Christian Democratic Union (CDU) in the Soviet occupation zone of Germany.

On 11 October 1949 he became East Germany's first Minister of Foreign Affairs in Otto Grotewohl's cabinet [1] However, he tended to be only a figurehead to secure CDU participation in the SED-dominated National Front and most important decisions would be made by his eventual successor Anton Ackermann.

[2] In 1950 he signed the Oder-Neisse Treaty with Poland, that arranged the borderline between East Germany and the Polish People's Republic.

On 15 January 1953 Dertinger was arrested due to his allegedly harmful activities against East Germany[3] and in 1954 he was tried on a show trial for espionage, found guilty and sentenced to hard labor (15 years).